db={"courses":[{"_id":1,"name":"Course 1","modules":[{"id":1,"name":"Module 1","lessons":[{"id":1,"name":"Lesson 1"},{"id":2,"name":"Lesson 2"}]}]},{"_id":2,"name":"Course 2","modules":[{"id":1,"name":"Module 1","lessons":[{"id":1,"name":"Lesson 1"},{"id":2,"name":"Lesson 2"}]},{"id":2,"name":"Module 2","lessons":[{"id":3,"name":"Lesson 3"},{"id":4,"name":"Lesson 4"}]}]}],"progress":[{"_id":1,"courseId":1,"userId":1,"lessons":[{"id":1,"status":"COMPLETED"}]}]}

db.courses.aggregate([{$match:{"_id":1}},{"$lookup":{"from":"progress","localField":"_id","foreignField":"courseId","pipeline":[{"$match":{"userId":1}},{$project:{lessons:"$lessons"}}],"as":"progress"}},{$unwind:{path:"$progress",preserveNullAndEmptyArrays:true}},{$set:{"modules":{$map:{input:"$modules",as:"module",in:{id:"$$module.id",name:"$$module.name",lessons:{$map:{input:"$$module.lessons",as:"moduleLesson",in:{$mergeObjects:["$$moduleLesson",{$first:{$filter:{input:"$progress.lessons",as:"progressLesson",cond:{$eq:["$$moduleLesson.id","$$progressLesson.id"]}}}}]}}}}}}}},{"$project":{"name":1,"modules":1}}])